Cantilevered leaf spring assembly

ABSTRACT

A cantilevered leaf spring suspension is disclosed for two separate pairs of wheels (16) which are independently sprung from each other via free ends of respective leaf springs (20) cantilevered from a cross beam (18) of the frame (12) of the top dresser (10). Each of the free ends of the leaf springs (20) includes axle blocks (24) with longitudinally mounted shafts (26) about which the wheels (16) pivot from side to side to match the terrain and more evenly distribute the mass of the hopper (30). Further, a snubber bar (29) includes a free end for abutting the leaf spring (20) intermediate the cross beam (18) and the free end of the leaf spring (20) for limiting the vertical travel of the leaf spring (20).

CROSS REFERENCE

The present application is a division of application Ser. No. 07/948,664filed Sep. 22, 1992, now U.S. Pat. No. 5,307,952, which is acontinuation-in-part of application Ser. No. 07/651,467 filed Feb. 6,1991, now abandoned.

BACKGROUND

The present invention generally relates to an apparatus for dispensingor spreading material, particularly to an apparatus for top dressingterrain, and specifically in a most preferred form to front unloadingtop dressers.

Various apparatus exist for applying top dressing to the turf of golfcourses, lawns, football, baseball and soccer fields, parks,recreational areas, and the like, for applying calcined clay on baseballdiamonds, for sanding icy sidewalks and driveways, and for likeapplications of a ribbon of material at a preselected rate. An exampleof one of such apparatus is shown in U.S. Pat. No. 4,438,873 which hasbeen widely and very successfully marketed under the trademark TURFCOMETE-R-MATIC. With the increasing awareness of the importance of topdressing in turf management, an increasing need exists for improveddispensers to allow the effective, efficient application of materialwith minimal damage to the turf and with increased ease of operation.

SUMMARY

Accordingly, a general object of the invention is to provide a topdresser that is simple, both as to its structure and to the manner inwhich it is operated.

Another object of the invention is to provide a front unloading topdresser. Specifically, prior top dressers dispensed the material behindthe hopper. This was disadvantageous for several reasons. First,operation of the dispensing means was not visible to the operator on theutility vehicle pulling the top dresser as the hopper blocked his view.Thus, any problems encountered with the dispensing means includingrunning out of material for at least portions of the dispensing meanswas only evidenced after the operator was able to see the applied areaafter the top dresser had advanced a sufficient distance for theoperator to see the applied area over the hopper. Thus, it is an aim ofthe present invention to allow the material being dispensed to be easilyviewed by the operator.

Another object of the invention is to provide a unique hopperconstruction. Specifically, prior top dressers utilized gravity toadvance the material to the dispensing means. Thus, the hoppers of priortop dressers tended to be arranged vertically to take advantage ofgravitational forces. This was disadvantageous because loading of suchhoppers was more difficult, viewing by the operator behind the topdresser was more difficult, and the like. In one aspect of the presentinvention, the top dresser of the present invention includes a dischargegate slideable in the hopper for pushing the material towards thedispensing means. In a preferred aspect of the invention, the dischargegate is slideably mounted to the hopper by means located outside of thehopper and thus not subject to the sand, grit or the like of thematerial of the hopper. In another preferred aspect of the invention,the discharge gate is slid by an expandable and contractable actuatormounted at an angle to the direction of movement of the discharge gateto reduce the overall length required for the top dresser.

Yet another object of the invention is to provide a unique dispensingmeans. Specifically, it is an aim of the present invention to providedispensing means in the form of corrugated sheeting movable relative tothe end of the hopper, with the corrugated sheeting including amultiplicity of spaced, parallel ribs extending continuously in thedirection generally perpendicular to the movement direction of thesheeting and defining spaced channels therebetween of generally constantdepths for receiving material. Additionally, prior top dressers utilizedendless conveyors on the bottom of the hopper to bring the material tothe dispensing means. Such endless conveyors were then especially proneto wear as the full mass of the material in the hopper was exertedthereon and included components which were movable relative to eachother and thus subject to increased friction due to the presence ofsand, grit, and the like in the material to be dispensed. In one aspectof the present invention, the corrugated sheeting is arranged around theperiphery of a rotatable, cylindrical drum to grip the material and moveit from the hopper under a metering gate for dispensing onto the ground.It can be appreciated that the cylindrical drum is not as prone to wearas endless conveyors and is simpler to manufacture, assemble, andmaintain.

Still another object of the invention is to provide a unique manner ofmovably supporting the top dresser upon the ground in a manner to followthe terrain to reduce the uneven distribution of weight to the terrain.In a further aspect of the present invention, the material is dispensedin front of the movably supporting means such that the material isdispensed prior to the turf being compressed by the movably supportingmeans.

Surprisingly, all of the above objectives can be satisfied in the fieldof material dispensing by illustrative embodiments of top dressersaccording to the preferred teachings of the present invention, detaileddescriptions of which are described in connection with the drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a top dresser according to thepreferred teachings of the present invention, with portions being brokenaway to expose constructional details.

FIG. 2 shows a cross-sectional view of the top dresser of FIG. 1according to section line 2--2 of FIG. 1.

FIG. 3 shows a partial, cross-sectional view of the top dresser of FIG.1 according to section line 3--3 of FIG. 1.

FIG. 4 shows a partial, enlarged view of the top dresser of FIG. 1, withportions being broken away.

FIG. 5 shows a cross-sectional view of an alternate form of a topdresser according to the preferred teachings of the present invention.

FIG. 6 shows a top plan view of the top dresser of FIG. 5 according toview lines 6--6 of FIG. 5.

All figures are drawn for ease of explanation of the basic teachings ofthe present invention only; the extensions of the Figures with respectto number, position, relationship, and dimensions of the parts to formthe preferred embodiment will be explained or will be within the skillof the art after the following teachings of the present invention havebeen read and understood. Further, the exact dimensions and dimensionalproportions to conform to specific force, weight, strength, and similarrequirements will likewise be within the skill of the art after thefollowing teachings of the present invention have been read andunderstood.

Where used in the various figures of the drawings, the same numeralsdesignate the same or similar parts. Furthermore, when the terms "top","bottom", "first", "second", "inside", "outside", "end", "side","above", "longitudinal", and similar terms are used herein, it should beunderstood that these terms have reference only to the structure shownin the drawings as it would appear to a person viewing the drawings andare utilized only to facilitate describing the invention.

DESCRIPTION

A top dresser according to the preferred teachings of the presentinvention is shown in the drawings and generally designated 10. Topdresser 10 comprises a frame 12 having a drawbar 14 by which top dresser10 can be coupled to a towing tractor or utility vehicle for pullingthereby in a direction. In the preferred form, frame 12 is movablysupported upon the ground by four wheel assemblies, each having a pairof high floatation wheels 16. Each pair of wheels 16 is mounted to frame12 to allow movement vertically as well as to allow pivoting about alongitudinal axis to follow the terrain over which top dresser 10 isbeing pulled. Particularly, frame 12 includes a cross beam 18 extendinglaterally across top dresser 10. Each pair of wheels 16 is independentlysprung from each other and includes a leaf spring 20 having a first endmounted to cross beam 18 by any suitable means such as U-shaped clamps.The free end of each leaf spring 20 includes first and secondupstanding, laterally extending, parallel ears 22. An axle mountingblock 24 is located between ears 22 and pivotably mounted about alongitudinal axis defined by stub shafts 26 extending from oppositesides of block 24 and through ears 22. Axle 28 for the pair of wheels 16extends through block 24 generally perpendicular to the axis defined bystub shafts 26 and generally laterally of top dresser 10. In thepreferred form, leaf springs 20 for each pair of wheels 16 extend fromcross beam 18 generally parallel to each other with axles 28 for eachpair of wheels 16 extending the same longitudinal distance from crossbeam 18. Each wheel assembly includes a snubber bar 29 mounted in acantilever manner to cross beam 18 spaced above and generally parallelto leaf spring 20. Snubber bar 29 includes a free end for abutting leafspring 20 intermediate cross beam 18 and the free end of leaf spring 20for limiting the vertical travel of leaf spring 20.

A hopper 30 is mounted on frame 12 and generally includes an open top32, a closed floor or bottom 34, first and second, parallel closed sides36 and a front. Sides 36 are mounted spaced above bottom 34 by asuper-structure 40 to provide a gap 42 having a constant height betweensides 36 and bottom 34. A pusher 44 extending between sides 36 ismovably mounted for longitudinal movement on bottom 34 and between sides36. Specifically, pusher 44 includes a carrier frame 46 slideable alongbottom 34 and including ears 48 extending from the opposite sides ofpusher 44 through gaps 42 beyond sides 36 for slideable receipt betweensides 36 and bottom 34. In the most preferred form, pusher 44 isslideably supported relative to hopper 30 by C-shaped slides 50 mountedoutside of sides 36 and on ears 48. Slides 50 have a size complementaryto and for slideable receipt on longitudinally extending, elongatedtubular rails 52 secured to superstructure 40 outside of sides 36 andgenerally longitudinally of top dresser 10. Thus, sides 36 are locatedintermediate rails 52. In the preferred form, C-shaped friction blocks54 are slideably received on rails 52 and secured within slides 50.Friction blocks 54 reduce the wear and friction between slides 50 andrails 52 to reduce maintenance and energy requirements. Slides 50 andblocks 54 on opposite sides of hopper 30 have their free ends pointingat each other. In the most preferred form, two sets of slides 50 andblocks 54 are slideable on rail 52 on each side of hopper 30 to controlthe motion of pusher 44 to follow a straight line within hopper 30.Pusher 44 further includes a discharge gate 56 secured to carrier frame46 and extending from bottom 34 and between sides 36 and movablerelative thereto. In its most preferred form, gate 56 slopes rearwardfrom bottom 34. Suitable provisions such as sealing gaskets or flaps canbe provided to prevent sand, dirt, or other material from passingbetween pusher 44 and bottom 34 and sides 36 of hopper 30 and/or aroundears 48 and through gap 42.

In the most preferred form, pusher 44 is longitudinally moved in hopper30 between a first, expanded position and a second, unloaded position byfirst and second, cross mounted, expandable and contractable, hydraulicactuators 58 and 60 mounted outside of hopper 30 and in the preferredform below bottom 34 of hopper 30. The first ends of actuators 58 and 60shown as the free ends of cylinders 62 are pivotally mounted to frame 12about axes generally in front of hopper 30 and in the preferred formslightly spaced from and on opposite sides of the center of frame 12.Actuator 58 is shown as being mounted vertically above actuator 60. Theopposite ends of actuators 58 and 60 shown as the free ends of piston 64are pivotally mounted about axes to ears 48 of pusher 44 and outside ofhopper 30. In the most preferred form, actuator 58 mounted on the rightside of frame 12 extends to ear 48 on the left side of pusher 44 suchthat the plane of actuator 58 extending through its mounting axes is atan angle to the direction top dresser 10 is pulled. Likewise, actuator60 mounted on the left side of frame 12 extends to ear 48 on the rightside of pusher 44 such that the plane of actuator 60 extending throughits mounting axes is at an angle to the direction top dresser 10 ispulled. Further, the planes of actuators 58 and 60 intersect at an angleother than 180° or in other words are mounted in an X configuration,with the angle between actuators 58 and 60 being variable with theexpansion and contraction of actuators 58 and 60. It can then beappreciated that actuators 58 and 60 are extended when pusher 44 is inits rearward position and that actuators 58 and 60 are contracted whenpusher 44 is in its forward position.

A revolving, cylindrical, dispensing drum 66 is mounted to frame 12about a laterally extending axis located in front of and below bottom 34of hopper 30. Drum 66 in the most preferred form is cylindrical and hasa periphery covered with sheeting 70. Drum 66 is mounted with sheeting70 generally extending closely adjacent to but extending above bottom 34of hopper 30. In the most preferred form, bottom 34 of hopper 30 extendsin a non-tangential manner from drum 66 and includes suitable provisionssuch as a rubber or any other reliable, flexible strip fastened tobottom 34 and laying upon drum 66 for preventing material from backingits way out of hopper 30 between drum 66 and bottom 34.

A metering gate 72 is movably mounted relative to drum 66 in front ofbottom 34 and generally at the uppermost part of drum 66. Gate 72 ismovable away from drum 66 by any suitable means to create a larger gapfor material to pass therethrough such as by pivotably moving gate 72 byhydraulic actuators. A cylindrical brush 74 is movably and rotatablymounted in front of, above and parallel to drum 66 and on the oppositeside of drum 66 than hopper 30. Brush 74 includes bristles which engagesheeting 70 on the periphery of drum 66 after gate 72, with theengagement of bristles with sheeting 70 being minimal for dry materialwhile interfering with sheeting 70 for wet material. Drum 66 is rotatedin a forward direction, i.e. with the periphery of drum 66 above bottom34 of hopper 30 moving in the direction top dresser 10 is being pulledto draw material from hopper 30 towards and under metering gate 72.Brush 74 is rotated in an opposite direction to propel material fromdrum 66 onto the ground being dressed with a force sufficient topenetrate to the base of the turf.

Sheeting 70 in the most preferred form includes provisions for grippingthe sand or dressing material and moving it from hopper 30 under gate 72into rotating brush 74 and then onto the ground. In the preferred form,sheeting 70 is corrugated and includes spaced, parallel ribs 76 definingspaced cavities or channels 78 therebetween for receiving material. Theshape and configuration of ribs 76 must be such that with drum 66stationary and with metering gate 72 brought down to engage drum 66 andclose the opening therebetween, material, even dry materials with smallparticle size, will not leak or fall through the gaps between sheeting70 and metering gate 72. In the preferred form, ribs 76 extend generallyperpendicular to the direction top dresser 10 is being pulled and to thedirection of rotation of drum 66. In the most preferred form, ribs 76are in the form of multiple contiguous "W"s in a herringbonearrangement.

Furthermore, the shape and size of cavities 78 formed by ribs 76 mustallow the bristles of brush 74 to enter cavities 78 and remove thematerial therein. In the preferred form, the height of ribs 76 or inother words the depth of channels 78 is generally equal to or greaterthan the diameter of the largest granule of sand or material to bedressed and in the most preferred form is in the range of 0.125 to 0.156inch (0.318 to 0.397 centimeters). The spacing between ribs 76 or inother words the width of channels 78 is a multiple of the height of ribs76 or depth of channels 78 and in the most preferred form is in therange of 0.5 to 0.75 inch (1.27 to 1.91 centimeters).

Now that the basic construction of top dresser 10 according to thepreferred teachings of the present invention has been explained, theoperation, advantages, and subtle features of top dresser 10 can be setforth and appreciated. Specifically, it will be assumed that pusher 44is located in its first, expanded position adjacent the rear of hopper30 spaced from the front of hopper 30 and dispensing drum 66, hopper 30has been filled with material for top dressing, and top dresser 10 hasbeen pulled to the location to be top dressed. As top dresser 10 isbeing towed or pulled, drum 66 and brush 74 are rotated by any suitablemeans such as hydraulic motors. Drum 66 grips material in hopper 30 andmoves it from hopper 30 under metering gate 72. It can be appreciatedthat gate 72 can be positioned at the desired spacing from drum 66 tometer the amount of material passing between gate 72 and drum 66 for thedesired material application rate. After passing metering gate 72,material is propelled by brush 74 from channels 78 as drum 66 rotatesbeneath brush 74 to work the material into the turf.

It should then be noted that the positioning of drum 66 in front ofhopper 30 and particularly intermediate the operator of the towingvehicle and hopper 30 is advantageous. Particularly, the operator of thetowing vehicle can clearly see the operation of top dresser 10 andspecifically the top dressing of the material to the ground.Specifically, the material is dispensed by drum 66 and brush 74 in frontof hopper 30 such that hopper 30 does not block the view of the topdressing operation as occurred in prior rear unloading top dressers.Thus, the operator can see that the material is being uniformlydispensed and at the desired rate.

Additionally, as the major mass of top dresser 10 is the material inhopper 30, wheels 16 are positioned below hopper 30 and spaced fromdispensing drum 66 in a direction opposite to the direction top dresser10 is being pulled, i.e. generally behind drum 66 and brush 74. It canthen be appreciated that the material is top dressed on the turf priorto wheels 16 rolling thereon. It can be appreciated that wheels 16rolling over the turf pushes and bends the grass downward. In prior rearunloading top dressers, the dressing material was applied after thewheels pushed and bent the grass downward preventing penetration of thematerial in the turf and causing uneven distribution. Top dresser 10according to the teachings of the present invention dispenses thematerial to the turf in front of hopper 30 and wheels 16 and before thegrass is bent and pushed downward thereby to increase materialpenetration and uniform distribution.

It should also be noted that the manner that wheels 16 are mounted intop dresser 10 according to the preferred teachings of the presentinvention is also advantageous. Prior top dressers had their supportwheels mounted along a single axis. As the terrain is not perfectly evenbut includes dips and mounds, not all of the wheels would engage theterrain with equal force and in fact in some cases some of the wheelswould leave contact with the ground due to bridging or the like. Thus,uneven pressure could be placed on the turf by wheels mounted along asingle axis, with selected wheels putting excessive pressure while otherwheels placing minimal or no pressure. Apparatus 10 according to theteachings of the present invention allows wheels 16 to float to matchthe contour of the terrain and prevent the application of excessivepressure at certain points due to uneven terrain causing bridging or thelike. Specifically, leaf springs 20 allow each pair of wheels 16 toindependently move vertically according to the terrain. Further, eachpair of wheels 16 is allowed to pivot from side to side about stubshafts 26 to further match the terrain and more evenly distribute themass of top dresser 10 and of the material located in hopper 30.Additionally, as each wheel 16 is mounted on an end of axle 28, removalof any single wheel 16 is relatively easy and does not require theentire axle to be dismantled as in prior single axle top dressers.

As material is being dispensed by drum 66 and brush 74, gate 56 ispulled forward from its first, expanded position towards its second,unloaded position by contracting actuators 58 and 60. As gate 56 ispulled forward, material in hopper 30 is similarly pushed forward in thedirection top dresser 10 is being pulled toward drum 66 for dispensingthereby. It can be appreciated that pushing the material towards thedispensing means is advantageous rather than relying upon gravity tomove the material to the dispensing means. Specifically, due to theirnature, apparatus relying upon gravity tends to require greater heightof the apparatus which have and/or moves the center of gravity higherwith the addition of material thus requiring more complicated supportingstructure or the like, makes the loading of material more difficult,and/or may make it more difficult for the operator of the towing vehicleto see over the hopper in use.

Further, many top dressers utilized endless conveyors on the bottom ofthe hopper to advance the material to the dispensing means. It can thenbe appreciated that the full mass of the material in the hopper restedon such endless conveyors. Thus, considerable energy was required torotate the conveyor under the material and the conveyor was especiallysubject to wear, stretching, and breakage due to its continual exposureto the sand and other grit of the material causing increased friction.Drum 66 according to the preferred teachings of the present invention isbelieved to be advantageous over prior endless conveyors. Specifically,drum 66 is not subjected to the entire mass of the material withinhopper 30 as were prior endless conveyors. Thus, less energy is requiredto rotate drum 66 than to move prior endless conveyors. Additionally,drum 66 does not include relatively moving parts as in endless conveyorsof either a belt or apron construction. Thus, drum 66 does not requiretensioning apparatus required for endless conveyors, is not subject ofthe degree of wear as encountered for endless conveyors, and is easierto manufacture, assemble, and maintain than endless conveyors.

It should also be noted that the particular manner of moving pusher 44of apparatus 10 is believed to be particularly advantageous.Specifically, slides 50, rails 52, blocks 54, and actuators 58 and 60are positioned outside of hopper 30 and particularly away from thematerial in hopper 30. Thus, slides 50, rails 52, blocks 54, andactuators 58 and 60 are not prone to contamination by grit or the likecreating friction in the sliding movement.

Further, actuators 58 and 60 according to the teachings of the presentinvention are contracting when pusher 44 is moving forward. Thus,actuators 58 and 60 are in tension when under load and are not subjectto bending forces as would occur if actuators 58 and 60 were incompression. Therefore, actuators 58 and 60 can be of a smaller size anda longer length than if they were arranged in compression under load.

Furthermore, in the cross mounted configuration, the longitudinal lengthof actuators 58 and 60 and thus of top dresser 10 is considerablyreduced. Particularly, the dead space or in other words the longitudinaldistance required for actuators 58 and 60 in their fully retractedcondition with pistons 64 retracted in cylinders 62 is considerablyreduced when actuators 58 and 60 are arranged angularly with respect tothe longitudinal axis of top dresser 10 than if mounted parallel to thelongitudinal axis.

Actuators 58 and 60 are hydraulically connected to move in unison toadvance pusher 44 along bottom 34 of hopper 30. Thus binding of pusher44 due to uneven movement relative to hopper 30 is prevented. Pusher 44is advanced along bottom 34 to its second unloaded position adjacent tothe front of hopper 30 and just behind drum 66. It should be noted thatdischarge gate 56 is angled such that material abutting therewith is notretained thereon but slides evenly onto drum 66. Further, the upwardangle of discharge gate 56 allows the material under pressure from theforward movement of discharge gate to flow upward along the front faceof discharge gate 56. Thus, the force created by the moving materialagainst pusher 44, drum 66, and metering gate 72 is limited. Further,this configuration also limits the compressive forces between theparticles in hopper 30 so as to reduce the possibility of creatingadhesion between the particles. Adhesion results in a condition calledbridging between metering gate 72 and discharge gate 56 which holds thematerial in suspension, preventing it from flowing downward to drum 66and thereby stopping top dresser 10 from dispensing its load ofmaterial.

After all material has been dispensed from hopper 30, pusher 44 may bemoved rearwardly to its rearmost position by expansion of actuators 58and 60. It can be appreciated that while pusher 44 is being movedrearwardly, pusher 44 is in a no load condition as pusher 44 is notmoving material. Thus, the compression force on actuators 58 and 60which may cause actuators 58 and 60 to bend or buckle, is minimal. Atthat time, hopper 30 of top dresser 10 is ready to receive the next loadof material for dispensing.

It should be noted that drum 66 according to the preferred teachings ofthe present invention is believed to be advantageous. Particularly, thepresence of ribs 76 on sheeting 70 insures that sheeting 70 is able togrip the material to be dispensed and draw it under metering gate 72.The presence of channels 78 on sheeting 70 insures that the materialdoes not remain adhered to sheeting 70 and is able to be propelledtherefrom by brush 74. It can then be appreciated that ribs 76 andchannels 78 of the size and arrangement of the preferred form isbelieved to be particularly advantageous in this regard. Specifically,if the cavities were too small, they would tend to fill up with materialsuch as sand and especially sand that has some clay and some moistureand brush 74 can not remove it from the cavities. On the other hand, iftoo large, the material is dispensed onto the ground in an uneven mannerwhich is unacceptable to the user. The size and arrangement of channels78 according to the preferred teachings of the present invention is afunction of particle size, moisture, and clay content of the typicaldressing materials to be applied and the contact pressure of brush 74with drum 66 and allows satisfactory functioning for most top dressingmaterial presently being used by golf course and sport field managersthroughout the world.

Sheeting 70 in the preferred form is formed of rubber and in the mostpreferred form is formed from cleated belting. However, sheeting 70 canbe formed of other materials such as plastic, steel, and aluminum aslong as the functional requirements for drum 66 are met.

Furthermore, cavities 78 can take other forms according to the teachingsof the present invention. For example, cavities 78 can have a closeddiamond shape elongated axially across the length of drum 66 and can beformed by diagonally crossing ribs 76. Further, there may be other formsthat would be acceptable depending upon the material being dispensed.

Now that the basic teachings of the present invention have beenexplained, many extensions and variations will be obvious to one havingordinary skill in the art. As an example, although top dresser 10 in themost preferred form includes several unique and novel features which arebelieved to produce synergistic results and be otherwise advantageous,such features can be utilized singly or in other combinations to obtainthe advantages thereof. For example, although sheeting 70 in the mostpreferred form of top dresser 10 covers drum 66 with the material beingadvanced within hopper 30 towards drum 66 and is believed to beadvantageous at least for the reasons previously set forth includingthat the entire mass of the material is not subjected to drum 66, it maybe desirable to utilize sheeting 70 in endless conveyor-type topdressers such as the type shown in U.S. Pat. No. 4,438,873 which ishereby incorporated herein by reference. FIGS. 5 and 6 illustrate suchan endless conveyor-type top dresser 100. Specifically, a conveyor 140is disposed so that sheeting 70 in the form of an endless belt passesbeneath a hopper 136, more specifically under its open bottom 136f, soas to have gravitationally discharged thereon whatever material iscontained in hopper 136 that is to be used in dressing the turf.Sheeting 70 in the form of an endless belt passes over a first,generally cylindrical roller 148 rotatably mounted on a transverse shaft150 which is adjustable in a fore and aft direction by means of threadedrods 154, each of which has a nut 156 thereon. Conveyor 140 furtherincludes a second, generally cylindrical roller 160 mounted for rotationon a transverse shaft 162, with roller 160 being parallel to andhorizontally spaced from roller 148. Roller 160 is rotated by anysuitable means such as ground driven in the manner shown in U.S. Pat.No. 4,438,873. Sheeting 70 passes over a platen or bed plate 166 that isfixedly supported by frame 112 of top dresser 100, with bed plate 166optionally including a coating or the like to reduce friction betweenbed plate 166 and sheeting 70. Conveyor 140 dispenses material fromhopper 136 onto the ground through the end of hopper 136, with sheeting70 being movable relative to end 136c of hopper 136. Top dresser 100further includes metering gate 72 movably mounted at end 136c of hopper136 and movable relative to conveyor 140 to meter the amount of materialbeing dispensed. Specifically, gate 72 is movable away from conveyor 140by any suitable means to create a larger gap for material to passtherethrough such as by pivotally moving gate 72 manually or byhydraulic actuators. Cylindrical brush 74 is movably and rotatablymounted above and parallel to conveyor 140 and rollers 148 and 160thereof. Brush 74 is on the side of gate 72 opposite hopper 136 and inthe same direction from gate 72 as the movement of sheeting 70 above bedplate 166 which is in the same direction which top dresser 100 is beingpulled in the form shown in FIGS. 5 and 6. However, it can beappreciated that an endless conveyor-type top dresser utilizing sheeting70 can be constructed in the manner of U.S. Pat. No. 4,438,873 whichdispenses the material behind hopper 136. Brush 74 is rotated in anopposite direction as roller 160 to propel material from sheeting 70 ofconveyor 140 onto the ground being dressed with a force sufficient topenetrate to the base of the turf. Frame 112 upon which hopper 136 ismounted is movably supported upon the ground by any suitable means suchas wheels 118. It can then be appreciated that sheeting 70 obtains thesame and similar advantages in endless conveyor-type top dresser 100 asin cylindrical dispensing drum-type top dresser 10.

Thus since the invention disclosed herein may be embodied in otherspecific forms without departing from the spirit or generalcharacteristics thereof, some of which forms have been indicated, theembodiments described herein are to be considered in all respectsillustrative and not restrictive. The scope of the invention is to beindicated by the appended claims, rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are intended to be embraced therein.

What is claimed is:
 1. A wheel assembly for movably supporting a frameupon the ground for movement in a first direction comprising, incombination: a leaf spring mounted to the frame in a cantilever mannerparallel to the first direction and having a free end; an axle block;means for pivotably mounting the axle block solely to the free end ofthe leaf spring about an axis parallel to the first direction; and apair of wheels rotatably mounted to the axle block on opposite sides ofthe leaf spring about an axis extending through the axle block andperpendicular to the first direction, with the wheels and the axle blockbeing mounted to the frame solely through the leaf spring.
 2. The wheelassembly of claim 1 further comprising, in combination: a snubber barmounted to the frame in a cantilever manner spaced above and parallel tothe leaf spring and having a free end for abutting with the leaf springto limit the vertical travel of the leaf spring.
 3. The wheel assemblyof claim 2 wherein the leaf spring includes a proximal end mounted tothe frame, with the free end of the snubber bar abutting the leaf springintermediate the proximal and free ends of the leaf spring.
 4. The wheelassembly of claim 3 wherein the proximal end of the leaf spring ismounted to the frame in a fixed manner.